The DRTC MS Core Facility supports NIH-funded diabetes investigators by providing services pertaining to the following specific aims: 1. To provide training in principles of MS and in using MS systems, including gas chromatography (GC)/MS, isotope ratio (IR)/MS, electrospray ionization (ESI)/tandem mass spectrometry (MS/MS), and matrix assisted laser desorption ionization (MALDI) time of flight (TOF) MS. 2. To provide and maintain functional MS systems for use in diabetes-related studies. 3. To consult with users on MS method development and mass spectrum interpretation. 4. To perform collaborative research studies involving MS Core Facility staff and diabetes investigators. 5. To perform service MS analyses, e.g. quantitation of target analytes and obtaining spectra for structural identification, for diabetes investigators. 6. To develop new MS methods for structural identification or quantitation of biomolecules involved in the pathogenesis of diabetes, its complications, its risk factors, or its treatment. 7. To promote use of MS methods in diabetes research by efforts in training, collaboration, development, service, and dissemination. 8. To reduce the cost of diabetes research by providing a centralized MS facility at a fraction of the cost of maintaining instruments in individual investigators' laboratories or using commercial MS facilities.